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Chapter 11: Confidence Intervals – Large Samples
Figure 11- 19:
Workbook Output with the Confidence
Interval for
Example 11-13
The display shows the 95% confidence interval is -1576.8 to -1425.2, the
same as was obtained by using the formula (to two decimal places). The
difference is due to rounding.
Note:
When the population standard deviations are unknown but the sample
sizes are large (
30, and
30), the population variances in the formula
can be replaced by the sample variances if the population variances are
unknown. The equivalent formula is shown next.
Click here for the Large Sample Confidence Interval for the Difference Between Two Population Means Workbook